On paper, a full moon in the night sky may seem like anything to write home about. After all, full moons occur about every 29 days and are easier to spot in the sky than other lunar phases like a new moon. However, August’s full moon will be one for the record books because it also happens to be the third of four full moons this season. And its alignment with Earth, in conjunction with it being the third full moon of summer, means it will be bigger and brighter than ever. So, before grab your binoculars—here’s everything you need to know about the rare supermoon-blue moon mashup.
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August’s full moon will appear Sunday morning and last through early Wednesday morning, according to the National Aeronautics and Space Administration (NASA). However, Monday, Aug. 19, is when the full moon will also be considered a supermoon and blue moon.
Starting to get a little confused? Let’s break it down even further.
A supermoon happens when a full moon is at or near its closest point to Earth. This is called a “perigee,” while an “apogee” is when the moon is at its farthest from Earth, per NASA. When the moon hits the perigee stage, it can appear up to 14 percent bigger than at apogee. NASA reports that about 25 percent of full moons become supermoons.
Meanwhile, a seasonal blue moon is the third full moon in a season with four full moons. While they aren’t uncommon, blue moons don’t happen frequently—about every two to three years, says NASA. (Hence the phrase "once in a blue moon.")
On the other hand, super blue moons are even more scarce, occurring every 10 to 20 years.
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Despite its colorful nickname, blue moons don’t typically have a blue-ish hue.
“On rare occasions, tiny particles in the air―typically of smoke or dust―can scatter away red wavelengths of light, causing the Moon to appear blue,” explains the space agency.
Put supermoons and blue moons together thi, and you get to see an unusual phenomenon that won't happen again until January or March 2037.
The super blue moon will reach its peak on Monday, Aug. 19, at 2:26 p.m. Eastern Standard Time (EST). However, stargazers will have to wait until after sunset to grasp the gravity of the moon’s brightness and size.
The good news is you won’t need binoculars to witness the super blue moon. On any average night, the moon resembles the size of a nickel, but a super blue moon will resemble the size of a quarter. Of course, stargazing in areas that aren’t populated with high-rise buildings, bright city lights, and tall trees will improve your viewing experience.
